Evidences for the Role of Melatonin as a Protective Additive During Buffalo Semen Freezing

Abstract

Till now, the exact role of melatonin in male infertility hasn't been fully discovered. Moreover, the intracellular signaling pathways activated by melatonin in buffalo spermatozoa especially on the level of cryopreservation process haven't been reported. The current study aimed simply to clarify the precise role of this hormone during buffalo semen cryopreservation. Semen samples were obtained randomly from 6 fertile buffalo bulls (aged 3 to 5 years). Weekly, two consecutive ejaculates were collected from each bull for successive six weeks duration using an artificial vagina. The ejaculates were pooled to eliminate variability between the evaluated samples. After that, semen samples were subjected to extension with Tris-based extender supplemented with different concentrations of melatonin (0.1, 0.25, 0.5, 0.75 and 1 mM) Vs. Trisbased extender only (control). Then they were processed to cryopreservation and thawing to assess the different semen characteristics. It had been found that 0.1 mM of melatonin significantly (p<0.05) improved post thawing motility, viability index, acrosomal integrity, total antioxidant capacity, superoxide dismutase and glutathione reductase activity. On the other hand, it significantly (p<0.05) decreased the rate of lipid peroxidation, aspartate amino transferase, alanine aminotransferase, alkaline phosphatase and DNA fragmentation. All of these previously enhanced semen characteristics were reflected positively on its in vitro fertilizing capacity, as well as the percent of harvested embryos. In conclusion melatonin supplementation to the extension media of buffalo semen during processing significantly enhanced its characteristics. Moreover, the preceding results focusing more light on the potential roles of melatonin in regulating male reproduction.

Improving cryopreservation capacity of ram spermatozoa by supplementing the diluent with melatonin

“…Additionally, the percentages of post-thaw primary and secondary sperm abnormalities were 2.6 and 3.6 higher in the control group than those of MelatoninHD group, respectively. These results are in conformity with those reported previously in different species (Sariözkan et al 2009;El-Raey et al, 2014).…”

“…Furthermore, via modulating the glutathione activity, melatonin has been reported to improve sperm mitochondrial health state and functions and, thus, improve IVF outcomes (El-Raey et al, 2014).…”

“…In addition to its multiple actions on different physiological processes, melatonin and its metabolites are considered powerful antioxidants due to their ability to scavenge excessive ROS and, thus, protect the spermatozoa (Reiter and Tan, 2003;Ahn and Bae, 2004;Adriaens et al, 2006;Kang et al, 2009). Therefore, melatonin supplementation was reported to counteract the drastic effects of lipid peroxidation on cryopreserved semen parameters in different species (Sariözkan et al 2009;El-Raey et al, 2014). …”

Kinetic Motilities of Cryopreserved Bull Spermatozoa: Owing to the Effect of <i>Eurycoma longifolia</i> Jack Aqueous Extract

“…For instance, Gualtieri et al (2014) revealed that adding 10 µg mL −1 zinc chloride, 500 µg mL −1 D-aspartate and 40 µg mL −1 coenzyme Q10 to the bull semen after thawing improved all kinetic motilities of semen as compared to the control group. El-Raey et al (2014) found that addition of 1 mM of melatonin for tris-based egg yolk diluent improved sperm motility, viability values and the fertility rate as well compared to control group in buffalo bulls. Moreover, Daramola and Adekunle (2015) found that the progressive motility of chilled buck semen were improved in extender that was supplemented with pineapple and cucumber juices compared to control group.…”

Effect of melatonin and/or cysteamine on development and vitrification of buffalo embryos

“…Where, melatonin was found to directly interact with ROS and stimulates the activity of some antioxidant enzymes as superoxide dismutase, glutathione peroxidase, and catalase [16,17]. Also, melatonin prevents lipid peroxidation [39]; protein, and DNA [19,40]. In addition, it was found that melatonin preserve the function of mitochondria through reducing and preventing ROS [20], as well as enhancing mitochondrial distribution activity and patterns during nuclear maturation phase [31], and preventing or reducing apoptosis level [21].…”